Methods for preparing particles precursor, and particle precursor prepared thereby

Abstract

The present disclosure provides a method for preparing full-gradient particle precursors, and the full-gradient particle precursor prepared thereby. By controlling different types of anion compositions and/or cation compositions gradually changed to other types, and adjusting the pH to match with the species, precipitated particles are deposited to form a slurry, collecting the precipitated particle, treating with water, and drying to yield the particle precursor. After being washed and dried, the particle precursor is further mixed with lithium source, after calcining to yield cathode active particles. The cathode active particles can be used to prepare cathode of lithium-ion battery.

What is claimed is: 
     
       1. A method for preparing a full-gradient particle precursor, comprising the following steps:
 from an initial time t 0  to a first time t 1 , feeding stream (b) into a reactor for providing anion(s), feeding stream (a) for providing cation(s), whereby the anion(s) and the cation(s) reacting to form a precipitated particle slurry; the stream (a) comprises at least a first cation composition A 1 , the stream (b) comprises at least a first anion composition B 1  and a second anion composition B 2 , which is different from the first anion composition B 1 , the first anion composition B 1  is gradually switched to the second anion composition B 2  from the initial time t 0  to the first time t 1 , t 1  comes after t 0 , t 0 =0; 
 filtering precipitated particle slurry to obtain a precipitated particle, and drying the precipitated particle to yield the full-gradient particle precursor; 
 the anion(s) provided by the stream (b) is at least one selected from the group consisting of NaOH, Na 2 CO 3 , NaHCO 3 , Na 2 C 2 O 4 , LiOH, Li 2 CO 3 , LiHCO 3 , Li 2 C 2 O 4 , KOH, K 2 CO 3 , KHCO 3 , and K 2 C 2 O 4 , 
 the cation(s) provided by the stream (a) is at least one selected from the group consisting of Mg, Ca, Zr, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Al, in a form of sulfate, carbonate, chloride, nitrate, fluoride, oxide, hydroxide, oxyhydroxide, oxalate, carboxylate, acetate, phosphate or borate. 
 
     
     
       2. The method of  claim 1 , wherein the stream (b) comprises anions whose concentration is 0.001-14 mol anion/L; and/or the stream (a) comprises cations whose concentration is 0.001-6 mol cation/L. 
     
     
       3. The method of  claim 1 , wherein the first anion composition B 1  is hydroxide salts, the second anion composition B 2  is at least one selected from the group consisting of carbonate, oxalate, and hydroxide. 
     
     
       4. The method of  claim 1 , wherein the stream (a) comprises only one cation composition A 1 , and a flowrate or concentration of the cation composition A 1  is constant from the initial time t 0  to the first time t 1 . 
     
     
       5. The method of  claim 1 , wherein the stream (a) further comprises a second cation composition A 2 , the first cation composition A 1  is abruptly switched to the second cation composition A 2  at a switching time t s , in which t s  is between the initial time to and the first time t 1 . 
     
     
       6. The method of  claim 1 , wherein the stream (a) further comprises a second cation composition A 2 , the first cation composition A 1  is gradually switched to the second cation composition A 2  from the initial time t 0  to the first time t 1.    
     
     
       7. The method of  claim 6 , wherein the first cation composition A 1  and the second cation composition A 2  has a cation ratio of Ni x Mn y Co z Me 1-x-y-z , where x+y+z≥0.9, z≤0.2, “Me” is at least one additional metal elements selected from the group consisting of Mg, Ca, Zr, Ti, V, Cr, Fe, Cu and Al. 
     
     
       8. The method of  claim 1 , wherein the stream (b) further comprises a third anion composition B 3 , which is at least one selected from the group consisting of NaOH, Na 2 CO 3 , NaHCO 3 , Na 2 C 2 O 4 , LiOH, Li 2 CO 3 , LiHCO 3 , Li 2 C 2 O 4 , KOH, K 2 CO 3 , KHCO 3 , and K 2 C 2 O 4 ; at the first time t 1 , B 3  begins flowing into the process;
 the method further comprising the following steps: 
 feeding the second anion composition B 2  and the third anion composition B 3  through a container, into the reactor from the first time t 1  to a second time t 2 , t 2  comes after t 1 , the second anion composition B 2  and the third anion composition B 3  form a dynamic anion composition, the dynamic anion composition is gradually switched to the third anion composition B 3  from the first time t 1  to the second time t 2 ; 
 feeding the stream (a) for providing cation(s) simultaneously from the first time t 1  to the second time t 2 , the stream (a) comprises at least the first cation composition A 1.    
 
     
     
       9. The method of  claim 8 , wherein the stream (a) further comprises a second cation composition (A 2 ), the method further comprises the following step: feeding the first cation composition A 1  and the second cation composition A 2  from the first time t 1  to the second time t 2 , during which the first cation composition A 1  is gradually switched to the second cation composition A 2 . 
     
     
       10. The method of  claim 1 , wherein a pH during the reaction is 7-13 which is gradually changed, the pH is 9.5-12.5 when precipitating hydroxides, the pH is 7-10 when precipitating carbonates; and/or a temperature during the reaction is 30-80° C. 
     
     
       11. A full-gradient particle precursor as prepared by the method of  claim 1 , wherein the particle precursor has a formula (Ni x Mn y Co z Me 1-x-y-z )(CO 3 ) a (OH) 2-2a  where x+y+z≥0.9, z≤0.2, 0≤a≤1, Me is at least one additional metal element selected from the group consisting of Mg, Ca, Zr, Ti, V, Cr, Fe, Cu and Al;
 the particle precursor comprises a first gradient part, which is made of co-precipitation of anions comprising a first anion composition B 1  and a second anion composition B 2  and cation(s) comprising at least a first cation composition A 1 , the first anion composition B 1  is gradually switched to the second anion composition B 2  from inner to outer, and the first anion composition B 1  is different from the second anion composition B 2.    
 
     
     
       12. The full-gradient particle precursor of  claim 11 , wherein the cation(s) further comprises a second cation composition A 2 , the first gradient part is divided into a center part and a periphery part enwrapping the center part, the center part comprises the first cation composition A 1 , the periphery part comprises mainly the second cation composition A 2 . 
     
     
       13. The full-gradient particle precursor of  claim 11 , wherein the cation(s) in the first gradient part further comprises a second cation composition A 2 , the first cation composition A 1  is gradually switched to the second cation composition A 2  within the first full-gradient part from inner to outer. 
     
     
       14. The full-gradient particle precursor of  claim 11 , wherein the full-gradient particle precursor further comprises a second gradient part enwrapping the first gradient part, the second gradient part is made of co-precipitation of anions comprising the second anion B 2  and a third anion B 3 , or the second gradient part is made of co-precipitation of anions comprising the first anion B 1 , the second anion B 2  and a third anion B 3 ;
 and cation(s) comprising at least the first cation composition A 1 , in which the second anion composition B 2  is gradually switched to the third anion B 3 ; 
 the second gradient part further comprises a second cation composition A 2 , the first cation composition A 1  is gradually switched to the second cation composition A 2  within the second gradient part from inner to outer. 
 
     
     
       15. The method of  claim 1 , wherein feeding stream (b) comprises the following steps:
 firstly, loading all the first anion composition B 1  into a container, which is connected with the reactor; secondly, starting to feed the second anion composition B 2  into the container with certain flowrate from the initial time t 0 , and the first anion composition B 1  and the second anion composition B 2  forming a dynamic mixture solution, feeding the dynamic mixture solution into the reactor through the container from the initial time to to a first time t 1 , at the initial time to, the dynamic mixture fed into the reactor is mainly the first anion composition B 1 , while at the first time t 1 , the dynamic mixture is mainly the second anion composition B 2.    
 
     
     
       16. The method of  claim 3 , wherein a content of hydroxide in the stream (b) is no less than 80 wt %, a content of carbonate anion and/or oxalate anion is no less than 40 wt %. 
     
     
       17. The method of  claim 6 , wherein the step that the first cation composition A 1  is gradually switched to the second cation composition A 2  from the initial time t 0  to the first time t 1  comprises the following steps:
 firstly, loading all the first cation composition A 1  into a container; 
 and then, starting to feed the second cation composition A 2  into the container at a certain flowrate from the initial time to to form a dynamic mixture; and 
 feeding the dynamic mixture into the reactor through the container from the initial time t 0  to the first time t 1 , the dynamic mixture is mainly the first cation composition A 1  at the initial time t 0 , mainly the second cation composition A 2  at the first time t 1.    
 
     
     
       18. The method of  claim 7 , wherein the first cation composition Ai has a cation ratio of Ni x Mn y Co z Me 1-x-y-z , where x+y+z≥0.9, 0.75≤x≤1; 0≤z≤0.1; and/or the second cation composition A 2  has a cation ratio of Ni x Mn y Co z Me 1-x-y-z , where x+y+z ≥0.9, 0.3≤x≤0.7; 0.25≤y≤0.5, Me is at least one additional metal elements selected from the group consisting of Mg, Ca, Zr, Ti, V, Cr, Fe, Cu and Al. 
     
     
       19. The method of  claim 8 , wherein the step that the second anion composition B 2  is gradually switched to the third anion composition B 3  from the first time t 1  to the second time t 2  comprises the following steps:
 starting to feed the third anion composition B 3  into the container with certain flowrate from the first time t 1 , the second anion composition B 2  and the third anion composition B 3  forming a dynamic mixture solution, or the first anion composition B 1 , the second anion composition B 2  and the third anion composition B 3  forming a dynamic mixture solution; 
 feeding the dynamic mixture solution into the reactor through the container from the first time t 1  to a second time t 2 , at the first time t 1 , the dynamic mixture fed into the reactor is mainly the second anion composition B 2 , while at the second time t 2 , the dynamic mixture is mainly the third anion composition B 3.    
 
     
     
       20. The method of  claim 9 , wherein a container for the stream (a) is filled with the first cation composition Ai at the first time ti, the step the first cation composition A 1  is gradually switched to the second cation composition A 2  comprises the following steps:
 starting to feed the second cation composition A 2  into the container for the stream (a) with certain flowrate from the first time t 1 , the first cation composition A 1  and the second cation composition A 2  forming a dynamic mixture solution; and 
 feeding the dynamic mixture solution into the reactor through the container for the stream (a) from the first time t 1  to a second time t 2 , at the first time t 1 , the dynamic mixture fed into the reactor is mainly the first cation composition A 1 , while at the second time t 2 , the dynamic mixture is mainly the second cation composition A 2.